JPH05263154A - Treatment of scrap metal - Google Patents

Abstract

PURPOSE:To economically treat scrap metal without using org. solvent and to recycle the scrap metal by cleaning the scrap metal stained with oil with an aq. cleaning soln. contg. specified surfactant, phosphate, silicate, etc. CONSTITUTION:A cleaner such as an anionic surfactant, nonionic surfactant, alkaline phosphate and alkaline silicate is added to water to prepare an aq. cleaner. The scrap metal stained with oil is cleaned by using this cleaner. In this case, the cleaner is preferably kept at pH 10 to 11. The cleaner is filtered off after cleaning, and the scrap metal is ultrasonically cleaned in an aq. cleaner having the same concn. as or more dilute than the cleaner. Consequently, the oil depositing on the scrap metal and the additional elements such as zinc, tin, lead, carbon, sulfur and phosphorus contained in the oil are effectively removed. The treatment is also appropriately applied to the scrap metal contg. elements easy to react with carbon and to the scrap metal easy to dissolve carbon.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating metal scraps, especially metal scraps suitable as a pretreatment for recycling and using the scraps generated during cutting.

[0002]

2. Description of the Related Art Cutting waste generated when cutting metal (including alloy) is melted and reused for resource saving. The present inventors, when recycling the cutting waste in this way, the cutting oil adhering to the cutting waste, especially zinc, tin contained in the cutting oil,
We have found that the removal of various trace elements forming extreme pressure additives such as lead and carbon, sulfur, phosphorus, etc. investigated.

First, the inventors of the present invention examined the degreasing treatment by dipping the cutting scraps in an organic solvent such as Perkren or trichloroethane.

[0004]

However, when cutting waste is treated using an organic solvent, a detoxifying device such as a ventilation device must be provided to protect the working environment, which is uneconomical. Occurs. Also, the organic solvent itself is expensive, and the treatment method is uneconomical in this respect as well. Furthermore, since the organic solvent is easily vaporized and is difficult to collect, the treatment method may be pointed out as a cause of ozone layer depletion.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an economical method for treating metal scraps without using an organic solvent.

[0006]

According to the method for treating metal waste of the present invention, a cleaning agent selected from the group consisting of anionic surfactants, nonionic surfactants, alkaline phosphates and alkaline silicates. The above-mentioned problems were solved by cleaning the metal scraps to which oil was attached using a water-based cleaning agent prepared by adding the above to water. The term "metal" used in the present invention shall include alloys.
Examples of the anionic surfactant include sodium dodecylbenzene sulfonate, sodium laurate, sodium dodecyl sulfate and the like. Examples of the nonionic surfactant include polyoxyethylene nonylphenyl ether, polyethylene glycol oleate,
Examples thereof include polyoxyethylene sorbitan monopalmitate. As the alkaline phosphate,
Examples include sodium tripolyphosphate, sodium phosphate, disodium hydrogen phosphate and the like. Examples of the alkaline silicates include sodium orthosilicate, sodium metasilicate, and sodium metadisilicate. Examples of metal scraps to which the treatment method of the present invention is suitable include those made of a metal containing an element that easily reacts with carbon, and the one made of a metal that easily forms a solid solution with carbon. Examples of the element that easily reacts with carbon include titanium, silicon, and tungsten. Examples of metals containing such elements include titanium-containing nickel alloys and titanium-containing copper alloys. In addition, as the metal in which carbon is likely to form a solid solution, there are nickel alloys such as copper-nickel alloys, iron alloys, cobalt alloys and the like. After the completion of the cleaning treatment, the aqueous cleaning liquid is filtered off, and then the metal scraps are ultrasonically cleaned, whereby the residual carbon amount can be further reduced. The amount of residual carbon can be further reduced by performing this ultrasonic cleaning in an aqueous cleaning solution having the same concentration as or diluted with the aqueous cleaning solution used in the cleaning treatment.
The pH of the water-based cleaning agent used in the cleaning treatment is preferably 10 or more and 11 or less. When the pH of the water-based detergent is adjusted to this range, the degreasing effect of this treatment method is further improved.

[0007]

According to the method for treating metal scraps of the present invention, not only the oil adhering to the metal scraps but also the additive elements such as zinc, tin, lead, carbon, sulfur and phosphorus contained in the oil Can be removed. In the treatment method according to the fourth aspect, after the cleaning treatment, the aqueous cleaning liquid is filtered and the metal scraps are ultrasonically cleaned, so that the amount of carbon remaining in the metal scraps can be further reduced. Claim 5
In the treatment method described above, since the ultrasonic cleaning is performed in an aqueous cleaning solution having the same concentration as or diluted with the aqueous cleaning solution, the amount of carbon remaining in the metal scrap can be further reduced. In addition, according to the processing method of claim 6, during the cleaning process, p
Since the water-based detergent having H10 or more and 11 or less is used, the degreasing effect is further improved.

[0008]

The method for treating metal scraps of the present invention will be described in detail below. Example 1 To 29.7 kg of water at 50 ° C., 300 g of non-ionic surfactant Alloxan C (trade name; manufactured by Gospel Kako Co., Ltd.) was added and well stirred to prepare an aqueous detergent. .. To this, 5 kg of titanium-containing nickel alloy cutting dust was finely crushed and added. And this is 50 ℃
And stirred for 20 minutes. Then, the cutting waste was taken out and dried with hot air.

Carbon analysis was performed on the cutting waste thus treated and the cutting waste before treatment. In this carbon analysis, the amount of carbon dioxide gas generated by melting and burning the sample by induction heating by adding a combustion improver to the sample is obtained from the difference in thermal conductivity, and the amount of carbon in the sample is calculated from the obtained amount of carbon dioxide gas. It is a test method. As a result of this carbon analysis, the carbon content of the cutting waste before the treatment was 1000 ppm, whereas the carbon content of the treated cutting waste was significantly reduced to 200 ppm. According to the treatment method of the present invention, It was found that the carbon adhering to the cutting waste can be reliably removed.

Next, the amount of zinc, tin, lead, sulfur, and phosphorus deposited was also examined, and it was found that these were also largely removed.

Next, the cutting waste treated as described above and the new raw material were mixed at a ratio of 1: 9 (weight ratio), and this was melted to produce a metal material. When we examined the structure and composition of this material, it was equivalent to that manufactured using only new raw materials,
No carbides or harmful elements were found.

Example 2 To 29.7 kg of water at 40 ° C., 300 g of anion-based surfactant, Ripon F (trade name; manufactured by Lion Corp.) was added and well stirred to prepare a water-based detergent. . 5 kg of finely crushed copper-nickel alloy cutting waste was added thereto. Then, this was stirred at 40 ° C. for 20 minutes. After that, the washing liquid was filtered out to obtain a thickness of 1
A layer of 0 mm cuttings was obtained. This was put in water at 50 ° C. and irradiated with ultrasonic waves (26 kHz / output 1200 W) for 60 seconds. Then, the cutting waste was taken out and dried with hot air.

When carbon analysis was performed on the cutting waste thus treated and the cutting waste before the treatment, it was 850 ppm before the treatment and 180 ppm after the treatment. Comparing this result with the result of Example 1, it was revealed that the deposited carbon can be further removed by performing ultrasonic cleaning in water after filtering. Then zinc,
When the amounts of tin, lead, sulfur and phosphorus deposited were examined, it was found that these treatments could also largely remove them.

Next, the cutting waste treated as described above and the new raw material were mixed in a ratio of 1: 9 (weight ratio), and this was melted to produce a metal material. When we examined the structure and composition of this material, it was equivalent to that manufactured using only new raw materials,
No carbides or harmful elements were found.

Example 3 To 29.7 kg of water at 50 ° C., 300 g of non-ionic surfactant Alloxan C was added and well stirred to prepare an aqueous detergent (Alloxan C1.
wt% aqueous solution). Titanium-containing copper alloy cutting scrap 5k
g was finely crushed and charged. And this at 50 ℃ 2
Stir for 0 minutes. After this, the washing liquid is filtered off and the thickness is 10 m.
A layer of m cuttings was obtained. This was placed in a 1 wt% aqueous solution of alloxan C at 50 ° C., and ultrasonic waves (26 kHz / 1200 W output) were applied for 60 seconds. Then, the cutting waste was taken out and dried with hot air.

When carbon analysis was performed on the cutting waste treated in this way and the cutting waste before treatment, the carbon content of the cutting waste before treatment was 980 ppm, whereas the carbon content of the treated cutting waste was 70 ppm. And it had dropped significantly. Comparing this result with the result of the second embodiment, it was found that the carbon adhering to the cutting waste can be removed to a greater extent by the processing method of the third embodiment.

Then, similar tests were conducted on zinc, tin, lead, sulfur and phosphorus, and it was found that these were also largely removed.

Next, the cutting waste treated as described above and the new raw material were mixed in a ratio of 3: 7 (weight ratio), and this was melted to produce a metal material. When we examined the structure and composition of this material, it was equivalent to that manufactured using only new raw materials,
No carbides or harmful elements were found.

(Example 4) Cutting debris was treated in the same manner as in Example 1 except that alkaline phosphate sodium phosphate was used in place of the nonionic surfactant. As a result, it was found that the same action and effect as in Example 1 could be obtained even when the alkaline phosphate was used.

Example 5 Cutting debris was treated in the same manner as in Example 1 except that an alkaline silicate, sodium metasilicate, was used in place of the nonionic surfactant. As a result, it was found that even when an alkaline silicate was used, the same effects as those of Example 1 could be obtained.

(Example 6) The pH of the cleaning liquid was changed as shown in Table 1 by changing the compounding amount of the nonionic surfactant (aloxane C), and otherwise the same as in Example 3 to produce cutting waste. Processed. Then, carbon analysis was performed on the processed cutting chips. The results are shown in Table 1.

[0022]

[Table 1]

From the results shown in Table 1, it was found that the amount of residual carbon can be further reduced by using an aqueous cleaning solution having a pH of 10-11.

[0024]

INDUSTRIAL APPLICABILITY As described above, in the method for treating metal scraps of the present invention, the metal scraps to which oil is attached are treated with an anionic surfactant, a nonionic surfactant, an alkaline phosphate and an alkaline silicate. Since the cleaning treatment is performed using an aqueous cleaning agent prepared by adding a cleaning agent selected from the group consisting of water, zinc and tin contained in the oil as well as oil adhering to metal scraps. It is also possible to remove additional elements such as lead, carbon, sulfur and phosphorus. Therefore, according to this method for treating metal scrap, the composition of the metal (including alloy) regenerated using the metal scrap does not change due to the influence of oil, and even if the metal scrap is used, the quality of the recycled metal material is high. Can be obtained. Moreover, according to the method for treating metal scraps, since the metal scraps can be treated without using the organic solvent, a good working environment can be maintained only by using a simple ventilation device, and an inexpensive cleaning agent can be used. So it's economical. In addition, the problem of ozone layer depletion can be avoided. In the treatment method according to the fourth aspect, after the cleaning treatment, the aqueous cleaning liquid is filtered and the metal scraps are ultrasonically cleaned, so that the amount of carbon remaining in the metal scraps can be further reduced. In the treatment method of the fifth aspect, since the ultrasonic cleaning is performed in an aqueous cleaning solution having the same concentration as or diluted with the aqueous cleaning solution, the amount of carbon remaining in the metal scrap can be further reduced.
According to the treatment method of claim 6, at the time of the cleaning treatment, pH 10 is applied.
Since the water-based detergent of 11 or less is used, the degreasing effect is further improved.

Claims (6)

[Claims] 1. Metal scraps to which oil adheres are treated with an anionic surfactant, a nonionic surfactant, an alkaline phosphate,
What is claimed is: 1. A method for treating metal scraps, which comprises performing a cleaning treatment using an aqueous cleaning agent prepared by adding a cleaning agent selected from the group consisting of alkaline silicates to water. 2. The metal scrap is made of a metal containing an element that easily reacts with carbon.
The method for treating the metal scrap described. 3. The method for treating metal scrap according to claim 1, wherein the metal scrap is made of a metal that easily dissolves carbon in solid solution. 4. The method for treating metal waste according to claim 1, wherein after the cleaning treatment, the aqueous cleaning liquid is filtered off, and then the metal waste is ultrasonically cleaned. 5. The method for treating metal scrap according to claim 1, wherein the ultrasonic cleaning is performed in an aqueous cleaning solution having the same concentration as or a concentration lower than that of the aqueous cleaning solution. 6. The method for treating metal scraps, wherein an aqueous detergent having a pH of 10 or more and 11 or less is used during the cleaning treatment of claim 1.